挂接在/proc上的对LED灯控制的驱动

通过一天的学习总结一下挂接在/proc上的对LED灯控制的驱动开发，代码和过程
1.驱动代码
[cpp]
#include <linux/module.h>
#include <linux/init.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <linux/gpio.h>
#include <mach/regs-gpio.h>
MODULE_LICENSE("Dual BSD/GPL");

#define USER_ROOT_DIR "led"
#define USER_ENTRY1   "led_entry1"

static struct proc_dir_entry *led_root;
static struct proc_dir_entry *led_entry1;

static char msg[255];
static unsigned long led_table [] =
{
    S3C2410_GPB(5),
    S3C2410_GPB(6),
    S3C2410_GPB(7),
    S3C2410_GPB(8),
};
static unsigned int led_cfg_table[] =
{
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
};

//int proc_read_information(char *page, char **start, off_t off, int count, int *eof, void *data);
int proc_write_information(struct file *file, const char *buffer, unsigned long count, void *data);

static int proc_test_init(void)
{
    int i;
    for( i=0;i<4;i++)
    {
        s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
    }
    // Create user root dir under /proc
    led_root = proc_mkdir(USER_ROOT_DIR, NULL);
    if (NULL==led_root)
    {
        printk(KERN_ALERT "Create dir /proc/%s error!\n",USER_ROOT_DIR);
        return -1;
    }
    printk(KERN_INFO "Create dir /proc/%s\n", USER_ROOT_DIR);

    // Create a test entry under USER_ROOT_DIR
    led_entry1 = create_proc_entry(USER_ENTRY1,0666, led_root);
    if (NULL == led_entry1)
    {
        printk(KERN_ALERT "Create entry %s under /proc/%s error!\n",USER_ENTRY1, USER_ROOT_DIR);
        goto err_out;
    }
    printk(KERN_INFO "Create /proc/%s/%s\n",USER_ROOT_DIR, USER_ENTRY1);

    //led_entry1->read_proc = proc_read_information;
    led_entry1->write_proc = proc_write_information;

    return 0;

    err_out: remove_proc_entry(USER_ROOT_DIR, led_root);
    return -1;
}

static void proc_test_exit(void)
{
    // Remove all entries
    remove_proc_entry(USER_ENTRY1, led_root);
    remove_proc_entry(USER_ROOT_DIR, NULL);
    printk(KERN_INFO "All Proc Entry Removed!\n");
}

//int proc_read_information(char *page, char **start, off_t off, int count, int *eof, void *data)
//{

//}
int proc_write_information(struct file *file, const char *buffer, unsigned long count, void *data)
{
    int count2=0,i ;
    if (copy_from_user((void *)msg, (const void __user *)buffer, count))
        return -EFAULT;
    count2 = 易做图_strtoul(msg, NULL, 0);

    //printk("information %d\n",count2);
    switch(count2)
    {
        case 0:
        case 1:
            for(i=0; i<4; i++)
            {
                s3c2410_gpio_setpin(led_table[i],!count2);
            }
        break;
        default:
            return -EINVAL;
    }

    return 0;
}

module_init(proc_test_init);
module_exit(proc_test_exit);

2.驱动Makefile
[cpp]
obj-m:=led2.o

CURRENT_PATH:=$(shell pwd)

ARM_LINUX_KERNEL:=/opt/FriendlyARM/mini2440/linux-2.6.32.2

all:
         $(MAKE) -C $(ARM_LINUX_KERNEL) SUBDIRS=$(CURRENT_PATH) modules

clean:
    rm -rf *.cmd *.o *.ko *.mod.c *.symvers *.order
3.开发过程
编写好驱动代码和Makefile,在PC机上编译成功后通过FTP把led2.ko文件上传到开发板，加载驱动（insmod led2.ko）,
执行echo 1 >/proc/led/led_entry1，灯全亮
执行echo 0 >/proc/led/led_entry1，灯全灭
注意：开发板缺省的文件系统已经有了led 测试程序，所以在开发板的命令行终端执行：

#/etc/rc.d/init.d/leds stop

补充：软件开发 , C++ ,